Specifying pipe supports - thermal performance

20 April 2020 Carl Davison, Technical Manager
Kooltherm Pipe Support

With the Government drive towards a net-zero carbon United Kingdom in 2050, raising the energy efficiency of buildings is now a key priority. Here at Kingspan Technical Insulation, we are already seeing this impact on service specifications as project teams look to reduce heat losses from above ambient temperature services. This is visible not only in the uptake of greater insulation thicknesses on these systems, but also in the growing use of insulated pipe support inserts.
Insulated pipe support inserts (sometimes simply referred to as ‘blocks’) are designed for use with pipe supports, hanger brackets and clamps. They have traditionally been installed to help ensure a continuous run of insulation – particularly on Chilled Water Applications where a complete vapour barrier is key to system integrity. You may have noticed an increased specification focus on the use of the products for other HVAC services over the last few years. This is in response to the changes to BS 5970:2012, which recognises the energy saving benefits of using insulated supports on above ambient services.
There are now a variety of insulated pipe support insert options available. In order to choose the most suitable option, a contractor or consultant should always consider the following factors:

  • Thermal performance
  • Load bearing performance
  • Fire performance
  • System integrity

In the course of this blog series, we’ll take a look at each of these aspects in turn beginning with some of the key questions around thermal performance.

Why is it important to insulate pipe supports?

Whilst pipe supports only come into contact with a small area of a total service run, if they are not insulated effectively, these points can account for a significant proportion of heat loss from above ambient temperature systems. This can undermine other measures put in place to improve energy efficiency, creating a performance gap between the estimated and actual energy demand and operational costs for a building, and is particularly relevant for smaller bore pipework where the frequency of supports is greatest.
Heat losses from these areas can also present a risk to occupant health. The escaping heat will warm the surrounding environment, increasing the risk that runs of static cold water pipework will warm to a temperature range where Legionella bacteria is able to spread and grow rapidly. Research from AECOM suggests that continual running communal heating and hot water distribution systems  may contribute towards overheating during the summer months.

Why does the thermal performance of the pipe support insert matter?

Pipe Support cut through with shadow

Clearly then, it is important to properly insulate these supports and this means looking carefully at the thermal properties of the insert you are using. In the past, wooden block support inserts were commonly used for this purpose. However, BS 5970:2012 now clearly states that these “should not be used”. To understand why, we need to look at the material’s thermal conductivity.

Thermal conductivity (also known as lambda value) is the measure of how easily heat passes through a material through the process of conduction. Materials with low thermal conductivities are more resistant to this type of heat transfer and therefore make better insulators. 
Wood was originally used as its thermal conductivity is much lower than that of exposed steel clips. However, its performance is still several orders of magnitude worse than that of modern insulation materials. One alternative is to use inserts featuring rock mineral wool. Whilst these offer improved performance relative to wood, a significant thickness of insulation is still required in order to meet most system performance requirements. This can hamper installations and may even mean that service spaces need to be expanded to provide sufficient room.
To address this, our Kooltherm Insulated Pipe Support Inserts use a rigid phenolic insulation core which offers leading thermal performance. This can help to address thermal bridging through the support with a slim insert thickness – saving vital space. They form a complete system in combination with Kooltherm Pipe Insulation, ensuring excellent continuity of insulation throughout the system and meeting the recommendation within BS 5970:2012 that “load bearing pipe supports be of the same material, or compatible with, the thermal insulation on the pipework”.

How much of an impact can different pipe support inserts have on heat loss?

To understand how the pipe support specifications can affect the performance of above ambient temperature systems, we carried out a thermal analysis of a +75°C Low Temperature Hot Water (LTHW) system to BS EN ISO 10211: 2017. The analysis looked at four separate specifications:
  1. Kooltherm Insulated Pipe Support Inserts
  2. Rubber lined clip fixed to pipe
  3. Metal clip fixed to the pipe
  4. Wooden block pipe support insert
Kooltherm PipeSupp
The results confirmed that heat loss from the Kooltherm Insulated Pipe Support Insert specification was four times lower than for the rubber clips, five times lower than the metal pipe clips and just one tenth of the losses from the wooden block infill.
The thermal analysis shown below clearly shows that both the metal and rubber lined clips allowed greater levels of heat transfer to the metal support rod. Whilst the wooden block pipe support limited heat transfer to the rod, more heat was able to escape across its large surface area due to its  poor insulating properties. In contrast, the Kooltherm Insulated Pipe Support Inserts provided an effective barrier to heat loss.

Want to find out more?

Hopefully this blog will have given you a clearer idea of why the thermal performance of pipe support inserts needs to be considered during specification. In the next blog in this series, we’ll take a look at load bearing considerations. Alternatively, you can find out more about the different factors which should be considered by reading our guide – Which Pipe Supports Are You Specifying?
If you require any technical information relating to the issues covered in our blog, send us an email at hvactechnical@kingspaninsulation.co.uk or contact our technical advisory service: 0808 168 7363

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